ByKathleen Bailey, Kathleen Bailey is former assistant director of the Arms Control and Disarmament Agency. She is now with the National Institute for Public Policy.April 23, 1991

THE terrifying threat posed by Iraqi Scuds during Desert Storm was a nasty taste of what is to come. Patriots effectively counter Scuds, but countries worldwide are acquiring missiles that can outdo Patriot. These missiles constitute a threat to United States assets and personnel abroad and to US allies. Soviet Scuds, whose range was easily extended by Iraq, are possessed by several nations in the Middle East; they can reach Europe. North Korea reverse-engineered and upgraded Scuds, which now menace South Korea and, potentially, Japan. Intermediate-range ballistic missiles are in the hands of Czechoslovakia and Bulgaria. At least 18 nations now have ballistic-missile capability and the number is growing.

Many missiles under development are very sophisticated. Some countries, such as India, could possess intercontinental ballistic missiles - weapons that can directly threaten the US - by the end of the decade. This is about the time it would take the US to build successful defenses against these missiles.

The spread of missile technology worldwide is made all the more terrifying by the concurrent development of warheads of mass destruction. The nations that are getting missile technologies are also working on nuclear, chemical, and biological warheads. India, China, and Pakistan already have nuclear-weapons capability; North Korea, Brazil, Argentina, South Africa, and others have nuclear facilities that are not subject to international inspection and could be used for weapons purposes. At least 20 nation s are known to have chemical-weapons programs, and dozens more have the technological prowess. Biological weapons are technically easy to produce.

One answer to the missile-proliferation problem is arms control, such as an international ban on intermediate-range missiles. Not everyone will sign up to arms control, however. And some who do may still cheat. We need insurance against deadly missiles.

Arms-control efforts should be accompanied by missile defense systems. This is what is intended in President Bush's program known as Global Protection Against Limited Strikes - GPALS. GPALS is a $41 billion program to provide defense against tactical and strategic ballistic missiles. It involves space and ground-based sensors and nonnuclear interceptors. It is not pie-in-the-sky technology. It can be in operation by the end of the decade or sooner.

GPALS also can protect the US and its allies against unauthorized or accidental launches from the Soviet Union or China. Imagine that the USSR breaks up into republics or China again undergoes revolution. Missiles could fall into the hands of independent militia or political factions. It is conceivable that they could fire a nuclear-armed missile at the US or its allies. GPALS could kill a missile as Patriot destroyed Scuds.

OPPONENTS of modernizing US missile defense have argued that third-world weapons of mass destruction would probably not be delivered by missiles. Rather, countries would use aircraft, ships sailed into harbors, or packages smuggled across borders. Yet Iran, Iraq, Syria, Israel, Egypt, Brazil, North Korea, South Africa, Pakistan, India, and other nations have active ballistic-missile development programs. They recognize that air defenses make aircraft delivery of weapons extremely difficult and that miss iles offer a more reliable means.

Another argument used against missile-defense modernization is that export controls can solve the missile proliferation problem. But missile technology is already available from a large number of countries, and that number will grow as new supplier countries move to profit from the increasing demand. Advanced third-world countries will, perhaps, share the know-how, as Israel, a country that it has launched its own satellites, has reportedly shared missile technology with South Africa.

Some oppose GPALS because they believe it will stimulate Soviet modernization and expansion of its strategic nuclear forces. The reasoning is that the USSR would do so in order to overwhelm US missile defenses. But the USSR would not have to increase its forces to overwhelm GPALS. This US missile-defense program is designed to be effective against limited strikes, not full-scale attacks by the USSR.

The final reason opponents give for rejecting GPALS is that it would force the US to abrogate the ABM treaty. The treaty does not allow for the space-based components that would be required for the GPALS systems. But the ABM treaty could be amended rather than abrogated. In fact, the Soviet Union might be very interested in making changes in the ABM treaty and itself pursuing enhanced missile defenses against limited strikes. The Soviet Union is at risk as much as the US in the face of missile prolifera tion. It may even be in greater danger because it is closer on all of its borders to countries that are acquiring missiles able to reach its territory.

The USSR may be willing to change the ABM treaty for another reason: It would not want to become target of nuclear retaliation in event of unauthorized launches of ballistic missiles from its territory.

A number of Soviet defense experts and politicians have indicated an interest in ballistic-missile defense. Perhaps the Soviet Union will see enough value in defending against proliferation and unauthorized launches that it will want to join the US in making mutually beneficial changes to the ABM treaty.

The danger of missiles - perhaps equipped with warheads of mass destruction - is great and growing. The objections raised to modernizing Patriot-type defenses appear to be poor. If the US moves quickly, a viable missile defense can be erected by the time that many countries' offensive systems come on-line.